US5877860A
Expired / Lapsed
US
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System and method for measuring the microroughness of a surface of a substrate
Assignee: Boxer Cross Inc
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Filing: 1996-05-13
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Granted: 1999-03-02
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Expires: 2016-05-13
Abstract
Abstract A system for measuring an amount of microroughness of a surface of a substrate, wherein a first beam of electromagnetic radiation and a second beam of electromagnetic radiation are generated, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping, and the first and second beams are focused onto the substrate so that the beams impinge upon a selected area of the surface of the substrate having a surface contour, the surface contour of the substrate causing a scattering of both beams. The scattering of the first and second beams is detected, the amount of scattering corresponding to a microroughness value of the selected area of the substrate, and the microroughness value of the selected area of the substrate is determined from the amount of scattering of the first and second beams. The microroughness measuring system may also be used for controlling a fabrication process.
Inventors
- 👤 Peter G. Borden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:43
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/30; G01B11/303
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
181 words
A system for measuring microroughness of a surface of a substrate, comprising: means for generating a first beam of electromagnetic radiation and a second beam of electromagnetic radiation, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping; means for focusing the first and second beams onto a surface of the substrate, the surface having a microroughness with a plurality of scattering points, each scattering point causing scattering of both beams and each scattering point being about one angstrom in size; means for repetitively scanning the first and second beams across a selected area of the surface of the substrate; means for detecting the scattering of the first and second beams during said scanning to generate an aggregate signal, said aggregate signal comprising the scattering signal from a plurality of scattering points impinged by each beam; and means, responsive to the detecting means, for determining the microroughness value of the selected area of the substrate based on the amount of scattering of the first and second beams.
Claim 2
Independent Claim
181 words
A system for measuring microroughness of a surface of a substrate, comprising: means for generating a first beam of electromagnetic radiation and a second beam of electromagnetic radiation, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping; means for focusing the first and second beams onto a surface of the substrate, the surface having a microroughness with a plurality of scattering points, each scattering point causing scattering of both beams and each scattering point being about one angstrom in size; means for repetitively scanning the first and second beams across a selected area of the surface of the substrate; means for detecting the scattering of the first and second beams during said scanning to generate an aggregate signal, said aggregate signal comprising the scattering signal from a plurality of scattering points impinged by each beam; and means, responsive to the detecting means, for determining the microroughness value of the selected area of the substrate based on the amount of scattering of the first and second beams.
Claim 3
Dependent Claim
47 words
The system of claim 1, wherein the size of the microroughness detected is proportional to the power of said beams, and further comprising means for varying the power of the beams generated by said generator in order to determine the microroughness values for different sizes of microroughness.
Claim 4
Dependent Claim
47 words
The system of claim 1, wherein the size of the microroughness detected is proportional to the frequency of said beams, and further comprising means for varying the frequency of the beams generated by said generator in order to determine the microroughness values for different sizes of microroughness.
Claim 5
Dependent Claim
29 words
The system of claim 1, further comprising means for scanning the first and second beams across a region of the substrate to generate a microroughness value for such region.
Claim 6
Dependent Claim
24 words
The system of claim 4, wherein the scanning means comprises means for supporting the substrate, and a piezoelectric element for moving the support means.
Claim 7
Dependent Claim
45 words
The system of claim 4, wherein the scanning means comprises means for moving an optical element of the measuring system, and means for detecting, in a synchronous manner, the signal generated by said first and second beams being scanned across the region of the substrate.
Claim 8
Dependent Claim
76 words
The system of claim 1, wherein the detecting means comprises means for producing a sum signal corresponding to a sum of the electric fields of the first and second beams, means for producing a difference signal corresponding to a difference of the electric fields of the first and second beams, and means for combining said difference signal from said sum signal to generate a signal corresponding to the microroughness value of the surface of the substrate.
Claim 9
Dependent Claim
30 words
The system of claim 2, wherein the determining means comprises means for producing a signal corresponding to a plurality of microroughness density values for a plurality of different microroughness sizes.
Claim 10
Dependent Claim
30 words
The system of claim 1, wherein the generation means comprises means for selecting a photon energy of the first and second beams so that the beams pass through the substrate.
Claim 11
Dependent Claim
20 words
The system of claim 9, wherein the selected photon energy is less than a band gap energy of the substrate.
Claim 12
Dependent Claim
31 words
The system of claim 1, wherein the generation means comprises means for selecting a photon energy of the first and second beams so that the beams reflect off of the substrate.
Claim 13
Dependent Claim
20 words
The system of claim 11, wherein the selected photon energy is greater than a band gap energy of the substrate.
Claim 14
Dependent Claim
65 words
The system of claim 1, wherein the generating means comprises means for generating a beam of electromagnetic radiation having two components with orthogonal polarizations, and means for separating the two components of orthogonal polarization into said first and second beams, and wherein the detecting means comprises means for recombining the separated first and second beams into a single beam with two components of orthogonal polarizations.
Claim 15
Dependent Claim
12 words
The system of claim 1, wherein the substrate is a semiconductor substrate.
Claim 16
Dependent Claim
14 words
The system of claim 1, wherein the substrate is a disk drive media substrate.
Claim 17
Dependent Claim
15 words
The system of claim 1, wherein the substrate is a flat panel liquid display substrate.
Claim 18
Dependent Claim
21 words
The system of claim 1, wherein the first and second beams are spaced apart from each other by about 1 micrometer.
Claim 19
Independent Claim
166 words
A method for measuring microroughness of a surface of a substrate, comprising: generating a first beam of electromagnetic radiation and a second beam of electromagnetic radiation, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping; focusing the first and second beams onto a surface of the substrate, the surface having a microroughness with a plurality of scattering points, each scattering point causing scattering of both beams and each scattering point being about one angstrom in size; repetitively scanning the first and second beams across a selected area of the surface of the substrate; detecting the scattering of the first and second beams during said scanning to generate an aggregate signal, said aggregate signal comprising the scattering signal from a plurality of scattering points impinged by each beam; and determining the microroughness value of the selected area of the substrate based on the amount of scattering of the first and second beams.
Claim 20
Independent Claim
166 words
A method for measuring microroughness of a surface of a substrate, comprising: generating a first beam of electromagnetic radiation and a second beam of electromagnetic radiation, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping; focusing the first and second beams onto a surface of the substrate, the surface having a microroughness with a plurality of scattering points, each scattering point causing scattering of both beams and each scattering point being about one angstrom in size; repetitively scanning the first and second beams across a selected area of the surface of the substrate; detecting the scattering of the first and second beams during said scanning to generate an aggregate signal, said aggregate signal comprising the scattering signal from a plurality of scattering points impinged by each beam; and determining the microroughness value of the selected area of the substrate based on the amount of scattering of the first and second beams.
Claim 21
Dependent Claim
44 words
The method of claim 18, wherein the size of the microroughness detected is proportional to the power of said beams, and further comprising varying the power of the beams generated by the generator in order to determine microroughness values for different sizes of microroughness.
Claim 22
Dependent Claim
45 words
The method of claim 18, wherein the size of the microroughness detected is proportional to the frequency of said beams, and further comprising varying the frequency of the beams generated by the generator in order to determine the microroughness values for different sized of microroughness.
Claim 23
Dependent Claim
27 words
The method of claim 18, further comprising scanning the first and second beams across a region of the substrate to generate a microroughness value for such region.
Claim 24
Dependent Claim
39 words
The method of claim 21, wherein scanning comprises moving an optical element of the measuring system, and detecting, in a synchronous manner, the signal generated by said first and second beams being scanned across the region of the substrate.
Claim 25
Dependent Claim
55 words
The method of claim 21, wherein determining comprises measuring areas of the substrate that are impinged by the beams as the substrate is being moved, determining a distribution of microroughness over said areas to produce a measurement signal, and measuring a phase shift of the measurement signal to produce said microroughness value of said substrate.
Claim 26
Dependent Claim
68 words
The method of claim 18, wherein detecting comprises producing a sum signal corresponding to a sum of the electric fields of the first and second beams, producing a difference signal corresponding to a difference of the electric fields of the first and second beams, and combining said difference signal from said sum signal to generate a signal corresponding to the microroughness value of the surface of the substrate.
Claim 27
Dependent Claim
19 words
The method of claim 24, wherein detecting comprises measuring a fraction of a Rayleigh scattering impinging on the detector.
Claim 28
Dependent Claim
26 words
The method of claim 19, wherein determining comprises producing a signal corresponding to a plurality of microroughness density values for a plurality of different microroughness sizes.
Claim 29
Dependent Claim
28 words
The method of claim 18, wherein generating the beams comprises selecting a photon energy of the first and second beams so that the beams pass through the substrate.
Claim 30
Dependent Claim
20 words
The method of claim 26, wherein the selected photon energy is less than a band gap energy of the substrate.
Claim 31
Dependent Claim
29 words
The method of claim 18, wherein generating the beams comprises selecting a photon energy of the first and second beams so that the beams reflect off of the substrate.
Claim 32
Dependent Claim
20 words
The method of claim 28, wherein the selected photon energy is greater than a band gap energy of the substrate.
Claim 33
Dependent Claim
59 words
The method of claim 18, wherein generating the beams comprises generating a beam of electromagnetic radiation having two components with orthogonal polarizations, and separating the two components of orthogonal polarization into said first and second beams, and wherein detecting the scattering comprises recombining the separated first and second beams into a single beam with two components of orthogonal polarizations.
Claim 34
Dependent Claim
12 words
The method of claim 18, wherein the substrate is a semiconductor substrate.
Claim 35
Dependent Claim
14 words
The method of claim 18, wherein the substrate is a disk drive media substrate.
Claim 36
Dependent Claim
15 words
The method of claim 18, wherein the substrate is a flat panel liquid display substrate.
Claim 37
Independent Claim
193 words
A method for measuring microroughness on a surface of a semiconductor substrate during the fabrication process of a semiconductor device, the fabrication process including a plurality of process steps for forming various portions of the device, the method comprising: generating a first beam of electromagnetic radiation and a second beam of electromagnetic radiation, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping; focusing the first and second beams onto a surface of the substrate, the surface having a microroughness with a plurality of scattering points, each scattering point causing scattering of both beams and each scattering point is about one angstrom in size; repetitively scanning the first and second beams across a selected area of the surface of the substrate; detecting the scattering of the first and second beams during said scanning to generate an aggregate signal, said aggregate signal comprising the scattering signal from a plurality of scattering points impinged by each beam; and determining the microroughness value of the selected area of the substrate based on the amount of scattering of the first and second beams.
Claim 38
Independent Claim
193 words
A method for measuring microroughness on a surface of a semiconductor substrate during the fabrication process of a semiconductor device, the fabrication process including a plurality of process steps for forming various portions of the device, the method comprising: generating a first beam of electromagnetic radiation and a second beam of electromagnetic radiation, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping; focusing the first and second beams onto a surface of the substrate, the surface having a microroughness with a plurality of scattering points, each scattering point causing scattering of both beams and each scattering point is about one angstrom in size; repetitively scanning the first and second beams across a selected area of the surface of the substrate; detecting the scattering of the first and second beams during said scanning to generate an aggregate signal, said aggregate signal comprising the scattering signal from a plurality of scattering points impinged by each beam; and determining the microroughness value of the selected area of the substrate based on the amount of scattering of the first and second beams.
Claim 39
Dependent Claim
34 words
The method of claim 35, further comprising controlling one or more of the fabrication process steps in real-time based on the measured scattering to adjust the microroughness value of the surface of the substrate.
Claim 40
Dependent Claim
28 words
The method of claim 35, wherein generating the beams comprises selecting a photon energy of the first and second beams so that the beams pass through the substrate.
Claim 41
Dependent Claim
20 words
The method of claim 37, wherein the selected photon energy is less than a band gap energy of the substrate.
Claim 42
Dependent Claim
29 words
The method of claim 35, wherein generating the beams comprises selecting a photon energy of the first and second beams so that the beams reflect off of the substrate.
Claim 43
Dependent Claim
20 words
The method of claim 39, wherein the selected photon energy is greater than a band gap energy of the substrate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-03-01 | 2002-08-31 | 2003-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-01 | 2006-08-31 | 2007-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-01 | 2010-08-31 | 2011-03-02 | $7700.00 | Window Closed / Lapsed |